The prevalence of anorexia nervosa will be determined by using height and weight data and scores on an eating attitudes test (EAT) from a sample of 8,000 students. Individuals whose data suggests eating disorder will be clinically interviewed to confirm the diagnosis. Similar data will be obtained from all students attending ballet schools (N equals 400) in order to determine whether anorexia nervosa is increased in adolescents who must focus increased concern on body size. Patients with anorexia nervosa have previously been shown to display disturbances in body image and interoception. At present, little is known about the development and long term stability of these disturbances. Subjects with anorexia nervosa, obesity and controls will undergo perceptual testing weekly for 4 weeks. Personality, eating habits, weight and menstrual function will be assessed through the study period in order to more fully understand the perceptual disturbances. While much speculation has focused on the role of the family in the development of anorexia nervosa, there has been no systematic study of this area. Parents of anorexic patients and controls will be studied in terms of their body perceptions, personality, attitudes to eating and weight and their interrelationships on the course of the disorder. There is agreement that weight restoration is an important aspect of the treatment of anorexia nervosa. However, after weight is regained the role of further therapies is not known. After impatient weight restoration, anorexic patients (N equals 60) will be randomly assigned to different treatment groups (family therapy, individual supportive psychotherapy or referral back to family doctor). Measures of clinical change in the patient, her family and perceptions will be taken yearly for 3 years.